Delayed Job on Heroku

Question

I have a Rails application hosted on Heroku that requires a weekly data import. The task is performed by administrators and takes about 1-2 minutes to run (compute time). On Heroku, jobs that require more than 30 seconds time out. Heroku recommends job queues - however paying $36.00 per month (price of one worker) for 8 minutes of compute time doesn't seem appropriate. A few questions:

1. Is it possible to only pay for delayed jobs when they are used (i.e. launch the delayed job service only when administrators are uploading the data import).
2. Is delayed job required? I'm not sure if the timeout is just displayed to the client or if the actual work is cancelled. The documentation does list 'take no action' as an option, but I'm not sure what the implications of this are.

Thanks!

Answer 1

Is it possible to only pay for delayed jobs when they are used (i.e. launch the delayed job service only when administrators are uploading the data import).

This is a question you should direct at the heroku support.

Is delayed job required? I'm not sure if the timeout is just displayed to the client or if the actual work is cancelled. The documentation does list 'take no action' as an option, but I'm not sure what the implications of this are.

If it's run weekly it's more likely a cronjob than something that is just delayed. You can use the daily cron Addon (it's free). Then create a file called lib/tasks/cron.rake.

task :cron => :environment do
  if Time.now.strftime('%w').to_i == 0 # run every sunday
    puts "Importing..."
    #... run import
    puts "done."
  end
end

source

This task will be run daily from heroku, so you need to check the day of week, if you want to run it on a weekly basis.

Answer 2

After testing, realized that the timeout does not prevent long running tasks from completing (just results being displayed to user). Ended up adding email notification and allow timeout to occur. Looked at threading request, but support in Rails seems flakey.

Answer 3

Delayed Job workers are billed by the second, so you can absolutely spin one up to handle your task, and have it turn itself off via the heroku API when finished.